Trifluoroethylene (HFO-1123), which has a low global warming potential (GWP), is greatly expected in recent years as a new refrigerant which may replace difluoromethane (HFC-32) and 1,1,1,2,2-pentafluoroethane (HFC-125) which are greenhouse gases.
In this specification, abbreviated names (e.g. refrigerant numbers) of halogenated hydrocarbon compounds are described in brackets after the compound names. As the case requires, the abbreviated names are employed instead of the compound names.
Heretofore, a method for producing such HFO-1123 from 1,1,1,2-tetrafluoroethane (HFC-134a) which is a relatively inexpensive material has been known. For example, Patent Document 1 discloses a method of subjecting HFC-134a to dehydrofluorination using a metal fluoride as a catalyst. Further, Patent Document 2 discloses a method of reacting HFC-134a with a metal hydroxide such as calcium hydroxide.
However, by the method disclosed in Patent Document 1, the degree of conversion of HFC-134a is low.
Further, the method disclosed in Patent Document 2 has the following problems.
(1) Calcium hydroxide has a high adhesion property between particles, and the particles are likely to be solidified to clog a part of the reactor.
(2) In the reaction of calcium hydroxide with HFC-134a, the amount of water formed as a by-product tends to be large, and accordingly a load of moisture removal process tends to be heavy before the obtained HFO-1123 is used as a refrigerant.
(3) When calcium hydroxide is used for the reaction with HFC-134a, side reaction of HFO-1123 with a large amount of water formed as a by-product tends to occur and a carboxylic acid fluoride and a carboxylate are generated, thus decreasing the yield of HFO-1123.
Therefore, for production of HFO-1123 useful as a new refrigerant which replaces greenhouse gases by using HFC-134a which is an inexpensive material, an efficient production method has been desired in which the degree of conversion of HFC-134a and the yield of HFO-1123 are high, clogging of the reactor is less likely to occur and the load of the moisture removal process is light, and problems such as a decrease in the yield of HFO-1123 will not arise.